1. Field of the Invention
The present invention relates to basket forceps to be inserted into the body cavity of a patient to collect or shatter an alien substance therein, such as a calculus.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2-111353, for example, discloses basket forceps for endoscopes used as a treatment instrument for removing, for example, gallstones. FIG. 12A schematically shows conventional basket forceps b used together with an endoscope a. The basket forceps b comprise a slim sheath c and handling wire d as shown in FIG. 12B. The handling wire d is movably inserted in the sheath c. A basket unit e is coupled to the distal end of the handling wire d. The basket unit e has a plurality of basket forming wires f. The proximal ends of the basket forming wires f are bundled and coupled to the tip of the handling wire d. The distal ends of the basket forming wires f are also bundled and secured to a tip member g. The respective portions of each basket forming wire f that are located close to the opposite ends of each wire f are expanded, thereby forming the basket unit e.
When the handling wire d is pushed and pulled relative to the sheath c, the basket unit e axially moves back and forth between a receipt position in which it is received in the sheath c, and an expanded position in which it is expanded in front of the sheath c.
In use, the basket forceps b are inserted into a body cavity of a patient, for example, into the bile duct with the basket unit e closed. After inserting the tip of the sheath c between the inner wall h1 of the bile duct and a gallstone h2, the basket unit e is opened to capture the gallstone h2 into the basket.
Further, in the basket forceps b, a wire insertion hole j for inserting therethrough a guide wire i is formed in the tip member g along its axis, as shown in FIG. 12B. The guide wire i is inserted through the wire insertion hole j of the tip member g and through the sheath c. Using the guide wire i inserted into the body before the basket forceps b, the forceps b are guided into the body.